Weather Briefing — La Rochelle → Gibraltar

Issued: Sat 17 Oct 2026, 18:41 UTC · Advisory only — verify against updated GRIBs and NAVTEX underway.

Current synoptic setup

The North Atlantic is dominated by a deep cut-off low south of Iceland (~980 hPa, Chart 1) with a trailing cold front sweeping toward the British Isles. A broad Azores ridge (1030–1035 hPa) sits across the Bay of Biscay and Iberia, with its axis running NW–SE from ~45°N 20°W into Portugal (Charts 1, 4). The 500 hPa pattern (Chart 1) shows a sharp trough over Greenland/Iceland with strong zonal flow aloft at ~552 dam over Biscay — meaning fronts will be steered quickly east. Over the route, surface winds are currently light to moderate N–NE 10–18 kt in Biscay, backing NW 12–18 kt off Finisterre (Chart 4). Satellite (Chart 8) confirms frontal cloud well north of 50°N; Iberian waters are largely clear.

72-hour outlook

Day 1 (Sun 18 Oct) — Biscay crossing.

N–NE 12–18 kt in outer Biscay, easing SSW of 46°N. Seas 2–3 m from NW (Chart 7, 24h: "3" offshore Biscay, "2" off NW Spain). No frontal passage on route — front stays N of 55°N. Clear window.

Day 2 (Mon 19 Oct) — Finisterre to Lisbon.

Ridge builds (1030 hPa centred ~45°N 15°W, Chart 2). N–NNE 15–20 kt along the Portuguese coast, locally 22–25 kt in the Nortada acceleration zone off Cape Roca. Seas 3–4 m NW swell (Chart 6: "4" at 40°N 15°W, "3" nearshore). Fast reaching/running leg.

Day 3 (Tue 20 Oct) — São Vicente to Gibraltar.

Winds ease to N 10–15 kt approaching Cape São Vicente, then variable 8–12 kt in the Gulf of Cádiz. Expect the usual Levanter/Poniente transition at the Strait — Chart 3 shows 1015 hPa over Iberia with weak gradient, suggesting light Poniente (W) 10–15 kt in the Strait. Seas <2 m.

Top 3 risks to watch

• Nortada acceleration off Portugal. Chart 5 shows an orange tongue (24–28 kt) hugging the Iberian coast at +48h. Uncertain exactly how far offshore it extends. Trigger to re-route further offshore: sustained >25 kt at Cabo da Roca buoy.
• Next Atlantic low (Chart 3, +96h). A 995 hPa low digs SE toward 50°N 20°W by Wed, with the trough tilting negatively — could sharpen fast. If 00Z GFS shifts the low south of 48°N, abandon any lingering in Biscay.
• Strait of Gibraltar wind reversal. Pressure gradient across Iberia is weak but could tighten if Mediterranean low deepens (Chart 2 shows 1020 hPa over Balearics). A rising easterly gradient >6 hPa Cádiz–Málaga means Levanter — hold at Barbate.

Routing considerations

Window is open — depart within 24 h. Delay risks catching the Day 4 Atlantic low in Biscay. Push south of 45°N quickly; by Monday the ridge gives you a fast NNE downwind run down the Portuguese coast. Stay 30–50 nm offshore of Portugal to clip the Nortada's inner edge without the worst of it. Round São Vicente by Tue midday to catch favourable Poniente through the Strait; if Levanter develops, anchor at Barbate and wait 24–36 h.

Weather Briefing — La Rochelle → Gibraltar

Issued: Fri 16 Oct 2026, 19:37 UTC · Advisory only — verify against updated GRIBs underway.

Current synoptic setup

A deep Icelandic low dominates the North Atlantic, with a central MSLP near 970 hPa south of Iceland (Chart 1), supported by a sharp 500 hPa trough (geopotential ~525 dam, −35 °C core). A broad Azores High (~1025–1030 hPa) sits over the mid-Atlantic/Iberia, with a ridge axis extending into western France — this is currently shielding the route. Over Biscay winds are light-to-moderate W/SW 10–18 kt (Chart 4). Chart 2 shows the Atlantic low filling but spawning a secondary system that drives a 1035 hPa high over the UK/Biscay by Sun 00Z, strongly ridging over the route. By Tue 00Z (Chart 3) the pattern amplifies: a fresh deep low (~975 hPa) southeast of Greenland with a sharp trough digging toward the UK — the downstream threat.

72-hour outlook

Day 1 (Sat 17 Oct) — Biscay crossing

W-SW 12–18 kt, backing SW later. Seas 2–3 m W swell (Chart 7, OPC 24 hr). No fronts over the route; frontal band stays north of 55°N. Good sailing conditions.

Day 2 (Sun 18 Oct) — Finisterre approach

Ridge building (1035 hPa over Biscay, Chart 2). Winds ease to NW–N 8–14 kt off NW Iberia. Seas drop to 1.5–2.5 m off Portugal (Chart 6 shows 2 m at ~40°N/10°W). Benign — motor-sail likely.

Day 3 (Mon 19 Oct) — Portuguese coast to Cape São Vicente

Ridge still dominant on western Iberian seaboard; expect N–NE 10–15 kt (Portuguese trades filling in as the ridge settles). Seas 1.5–2 m NW. Approaching Gibraltar: light & variable, possible easterly Levanter freshening in the Strait — monitor locally.

Top 3 risks to watch

• Trough digging toward Biscay beyond t+96h. Chart 3 shows a sharp 500 hPa trough aimed at the UK by Tue; surface cyclogenesis downstream is plausible but timing/track uncertain. Trigger: if the next GFS run shifts the 1000 hPa isobar south of 50°N by Tue 12Z, expect SW gales building in Biscay — be south of Finisterre by then.
• Finisterre acceleration. Chart 5 hints at an 18–22 kt NW tongue off NW Spain Sunday as the ridge tightens isobars against the Iberian coast. Trigger: sustained >25 kt observed at Cabo Vilán buoy → stand offshore 40+ NM to avoid cape-effect seas.
• Levanter in the Strait. Not resolved in these charts (resolution too coarse). High pressure building over France (Chart 2) + lower pressure over W. Med favours easterly gradient. Trigger: Tarifa METAR >20 kt E → hold at Barbate or time transit for slack/westerly lull.

Routing considerations

Window is open — depart Saturday AM. The Azores ridge gives a clean 48–72 hr corridor; the risk is what follows the ridge mid-next-week. Push hard south: aim to round Finisterre by Sun midday and be south of 40°N by Mon 00Z to stay ahead of any Day 4+ system. Favour the southern/warm side of any approaching low (safer semicircle on this route = south of the track, giving following SW). Keep ≥30 NM off Cape São Vicente to clear acceleration. Reassess at Finisterre with fresh GRIB.

Weather Briefing — La Rochelle → Gibraltar

Issued: Thu 15 Oct 2026, 20:00 UTC — Advisory only; verify against updated GRIBs and OPC bulletins underway.

Current synoptic setup

The North Atlantic is dominated by a deep Icelandic low complex, with a sub-965 hPa centre south of Iceland (Chart 1) driving a strong SW'ly jet across 50–60°N — 500 hPa heights plunge to ~525 dam over Iceland, confirming a sharp, active trough. Over the route itself, a weak ridge (~1020 hPa) sits across Biscay and Iberia, with a secondary 1025 hPa cell near the Azores. Chart 4 shows this ridging clearly: Biscay winds are light (6–12 kt), while a 30–40 kt SW'ly fetch rakes the waters west of Ireland. Chart 7 (GOES) shows the frontal cloud band draped NE–SW from Iceland toward the UK — the leading edge of the next system. Motion is classic: lows tracking ENE toward Scotland/Norway, fronts trailing SW into our longitude.

72-hour outlook

Day 1 (Fri 16 Oct) — Biscay: SW–W 10–15 kt, easing variable near the Spanish shelf. Seas 1–2 m from the W (Chart 6: "1–2" throughout Biscay, 0.5 m off NW Iberia). Benign. Finisterre approach clean.

Day 2 (Sat 17 Oct) — A broad 1035 hPa high builds over the UK/Biscay (Chart 2). Winds back light N–NE 8–14 kt down the Portuguese coast — favourable Portuguese Trades setting in. Chart 5 shows 1–2 m W of Iberia, 2.5 m dropping in the Western Approaches. SW Approaches to Finisterre leg is the moment to push.

Day 3 (Sun 18 Oct → Mon 19 Oct) — High strengthens to 1035 hPa centred over Biscay (Chart 3). N–NE 10–18 kt off Portugal, accelerating to 20–25 kt in the Nortada funnel between Lisbon and C. São Vicente. No frontal passage on the route; next Atlantic low stays N of 55°N.

Top 3 risks to watch

• Trailing cold front swinging into NW Iberia late Day 1. Chart 1 shows the frontal zone near 15°W; Chart 2 pushes it east. If timing slips 12 hr, expect a wind shift W→NW 20–25 kt and 3 m seas on the Finisterre corner. Trigger: pressure drop >3 hPa/3 hr at departure, or OPC 24 hr showing >3 m W of Finisterre.
• Nortada acceleration off Portugal (Day 3+). Chart 3's tight gradient between the 1035 hPa high and Iberian thermal low funnels N'ly 25–30 kt at C. Roca and C. São Vicente, with steep wind-against-current chop near headlands. Trigger: isobar spacing tightening on next run — consider offshore routing 30–50 nm.
• Downstream low (not yet on charts) for Gibraltar approach. The Icelandic parent (Chart 3, 980 hPa) will spawn successors; beyond t+96 h is unresolved. Trigger: any ECMWF/GFS run showing a secondary low digging S of 45°N by Day 4–5 → shelter at Cascais or Sines.

Routing considerations

Window is OPEN — depart within 24 hr. The Sat–Mon high gives a rare light-N transit for the full Iberian coast. Clear Biscay on Day 1 before the front arrives; aim to be W of 10°W by Sat 00Z. Favour the southern/western semicircle of any trailing front — stay offshore of the rhumb line through Biscay to keep wind aft. Off Portugal, hold 20–30 nm offshore to work the Nortada without headland acceleration. Gibraltar approach: monitor Levanter in the Strait separately — not resolved at this scale.

Weather Briefing — La Rochelle → Gibraltar

Issued: Wed 14 Oct 2026 20:16 UTC · Advisory only — verify against updated GRIBs and OPC bulletins underway.

Current synoptic setup

The North Atlantic is dominated by a deep cyclonic complex south of Iceland (Chart 1), with a primary low near 60°N/20°W around 975 hPa and 500 hPa heights down to 540 dam — a classic strongly baroclinic autumn pattern. A broad 1030 hPa Azores-type ridge extends from ~35°N west of Iberia across to the Bay of Biscay, keeping Biscay and the Iberian coast benign at t+0. Chart 4 confirms light-to-moderate (10–18 kt) flow over Biscay and the Portuguese coast, with the gale core (40–48 kt) sitting well NW near 50°N/25°W. Chart 7 (24 hr) shows 4–6 m seas along 50°N mid-Atlantic but only 2–3 m reaching the Biscay shelf and 1–2 m off Portugal/Gulf of Cádiz.

72-hour outlook

Day 1 (Thu 15 Oct) — Biscay: SW–W 12–18 kt, seas 2–3 m with long WNW swell. Finisterre: NW 10–15 kt, 2 m. Portuguese coast and Gulf of Cádiz: N–NE 8–12 kt, 1–2 m. No fronts on the route.

Day 2 (Fri 16 Oct) — Chart 2 shows the parent low deepening to ~970 hPa near the Hebrides; a trailing cold front sweeps SE across Biscay late. Pre-frontal SW 20–28 kt in northern Biscay (Chart 5), seas building to 3–4 m (Chart 6). South of 45°N: W 15–20 kt, 2–3 m. Iberian west coast and south: still N–NE 10–15 kt, 1.5–2 m.

Day 3 (Sat 17 Oct) — Front clears east; post-frontal NW 20–25 kt across Biscay, residual 3 m swell. Finisterre: NW 15–20 kt (acceleration zone — expect gusts higher). Chart 3 shows the Azores ridge rebuilding to 1030 hPa over Iberia — Portuguese coast and approaches to Gibraltar remain N 10–15 kt, 1–2 m, Portuguese trades filling in.

Top 3 risks to watch

• Friday's cold front in Biscay. Chart 2 + Chart 5 indicate SW 25 kt pre-frontal with a wind shift to NW. Timing of the front (±6 hr) is uncertain. Trigger: if 500 hPa trough on the next run digs further south, expect gusts 30+ kt — reconsider shelter at A Coruña.
• Finisterre acceleration post-front (Day 3). Charts 3 and 5 hint NW flow compressing against Galician coast. Trigger: NW gradient tightening on next prog → stand well offshore (≥40 nm) to avoid steep seas on the shelf break.
• Levanter at Gibraltar. Charts don't resolve the Strait, but the rebuilding ridge (Chart 3) with high pressure north favours easterly funnel winds. Trigger: Tarifa reporting E >20 kt on arrival day — delay Strait transit or stage at Barbate.

Routing considerations

Window is open — depart within 24 hr. Clear Biscay before Friday afternoon's front; aim to be south of 45°N by Fri 12 UTC. Favour the southern (warm) semicircle of the Hebrides low — i.e., stay south/southwest of the frontal axis, don't track north chasing westerlies. Round Finisterre by Sat midday to catch building NE Portuguese trades downwind to São Vicente. Approach Gibraltar with a Tarifa wind check 12 hr out.

Weather Briefing — La Rochelle → Gibraltar

Issued: Tue 13 Oct 2026 21:23 UTC · Advisory only — verify with fresh GRIB/GMDSS underway.

Current synoptic setup

A deep North Atlantic low sits south of Iceland (Chart 1), central pressure ~975 hPa, with a 500 hPa cold pool (–35 °C, 975 gpdm) directly overhead — a mature, vertically-stacked system. A broad 1020–1025 hPa ridge extends from the Azores across Iberia and into the western Med, giving the route a protective buffer for now. The parent low is forecast to deepen to ~955 hPa by Thu 15 Oct 00Z northeast of Iceland (Chart 2), driving a vigorous SW→W jet across 55–60°N but leaving Biscay and Iberia under slackening SW flow on the ridge's northern edge. By Sat 17 Oct (Chart 3), the Azores High amplifies to 1035 hPa centred over Biscay/UK, with ridging dominating the whole route.

72-hour outlook

Day 1 (Wed 14 Oct) — Biscay: SW–W 10–15 kt, seas 2–2.5 m from the W (Chart 6, 24 hr wave). Approaching warm front brushes northern Biscay late — expect veering and thickening cloud (Chart 7 shows frontal cloud band offshore W of Ireland).

Day 2 (Thu 15 Oct) — Northern Biscay: W–NW 15–20 kt behind weak cold front, seas 3–4 m W swell (Chart 5). Finisterre and south: NW 10–15 kt, seas 2–3 m. Chart 4 shows the strong winds (35–45 kt) stay well N of 55°N — route is clear.

Day 3 (Fri 16 Oct → Sat 17 Oct) — Full ridge build. Portuguese coast and Gulf of Cádiz: N–NE 10–15 kt (Portuguese trades reasserting), seas 1.5–2.5 m. Gibraltar Strait: easterly Levanter likely as pressure gradient tightens against 1035 hPa ridge — be ready for 20–25 kt E at the Strait.

Top 3 risks to watch

• Levanter at Gibraltar. Ridge building to 1035 hPa (Chart 3) over Biscay against lower pressure in the W Med sets up classic E gradient through the Strait. Chart resolution hides the Strait acceleration — if Tarifa reports >20 kt E, delay transit or stage at Barbate.
• Secondary low tracking SE off the parent system. Chart 2 shows a trough extending toward the UK; GFS run-to-run could shift this south into Biscay. Watch for any sub-1005 hPa feature appearing W of Ireland on next model cycle — would mean a Biscay gale on Day 3.
• W swell at Finisterre. Even with moderating local wind, Chart 5 shows 4 m W swell at 45°N/10°W persisting. Wind-against-swell near the cape shelf is uncomfortable; time Finisterre rounding for Fri daylight when seas ease to 3 m.

Routing considerations

Window is open — depart within 24–36 hr. The ridge builds behind you as you go south, which is ideal. Cross Biscay on a direct rhumb to Finisterre to clear the N swell zone before the Day 2 NW pulse peaks. Favour the southern/eastern (navigable) semicircle of the Iceland low — stay south of 47°N once past Finisterre. Hug the Portuguese coast (20–30 nm off) to use the N'ly trades on Day 3. Decision point: Cape São Vicente — check Tarifa winds before committing to the Strait; if Levanter >25 kt, hold at Sines or Lagos.

Weather Briefing — La Rochelle → Gibraltar

Issued: 12 Oct 2026 23:07 UTC · Advisory only — verify against updated GRIBs and NAVTEX underway.

Current synoptic setup

The North Atlantic is in an active, meridional pattern. Chart 1 shows a deep parent low near southeast Greenland (~970 hPa) with a strong 500 hPa trough (~970 gpdm core) digging south toward 50°N. A secondary 995 hPa low sits west of Ireland, driving a sharp cold front south-southeast across the western approaches. Over the route, a weak ridge (~1015–1020 hPa) extends from the Azores across Iberia into the western Med, keeping Biscay south of the main frontal zone — for now. By 48 h (Chart 2) the parent low deepens to ~970 hPa south of Iceland and the trough swings its front across Biscay; by 96 h (Chart 3) a vigorous 970 hPa low tracks toward Ireland with the Azores ridge rebuilding behind at 1025 hPa over Iberia and the approaches.

72-hour outlook

Day 1 (Tue 13 Oct) — Biscay crossing.

Chart 6 (24 h waves) shows W-SW winds 15–20 kt in Biscay, seas 3–4 m from a long NW Atlantic swell (7 m seas offshore 50°N/20°W — well west of track). Pre-frontal, broken cloud, manageable.

Day 2 (Wed 14 Oct) — Finisterre approach.

Chart 4 shows a jet of 30–40+ kt SW winds (pink shading) sweeping across western Biscay and NW Iberia as the cold front arrives. Chart 5: seas 4–5 m in Biscay, 3–4 m off Finisterre. Frontal passage with wind veering W to NW behind, gusts 35 kt possible near Finisterre acceleration zone.

Day 3 (Thu 15 Oct) — Portuguese coast to Cape São Vicente.

Post-frontal NW 15–25 kt (nortada reinforced), seas 2–3 m from the north — fast reaching conditions. Ridge building (Chart 3 precursor) stabilises the picture south of 40°N. Gibraltar approach: light-to-moderate E'ly in the Strait likely by Friday.

Top 3 risks to watch

• Day 2 frontal passage near Finisterre. Chart 4 shows the SW jet core clipping Cape Finisterre; Chart 5 confirms 4–5 m seas. Uncertain: exact timing of the front (±6 h). Trigger to re-route: if 24 h surface prog shifts the 1000 hPa isobar south of 45°N over Biscay — expect gale.
• Cross-swell at Finisterre. Chart 5 shows long-period NW swell (6.5 m marker at 50°N) wrapping south along the Iberian shelf. Uncertain: shelf refraction amplification. Trigger: buoy 6202 (Cabo Silleiro) reporting Hs >4 m with Tp >12 s — stand offshore of the 200 m contour.
• Day 4+ next system (Chart 3). A 970 hPa low tracks toward Ireland Fri/Sat. Uncertain: southern extent of its front — could reach northern Portugal. Trigger: if 96 h prog brings 1005 hPa isobar south of 42°N, push hard for Lisbon before Sat.

Routing considerations

Window: Open now, but tight. Depart within 12–18 h to cross Biscay ahead of the Day 2 front; delaying past Tue noon risks a beat into the SW jet.

Key legs:

• La Rochelle → 45°N/4°W: make southing fast while winds are W 15–20 kt.
• Finisterre rounding: aim to be south of 42°N by 14 Oct 12 UTC — favour the southern (warm) semicircle of the approaching low: W-shifting winds behind, better than the NW gale-force northern side. Stay 30+ NM offshore of the cape to avoid cross-swell on the shelf.
• Finisterre → São Vicente: fast reach in post-frontal NW; make miles while the ridge holds.
• São Vicente → Gibraltar: monitor Levanter development in the Strait as the ridge builds over Iberia (Chart 3).

Verify at next GFS/ECMWF run and OPC 24/48 h re-issue before casting off.